The field of application of the invention includes paramagnetic gas analysis, in particular oxygen measurement. In this type of measurement, the property of oxygen that is rare in gases is used whereby oxygen has a high paramagnetic susceptibility. If there is an inhomogeneous magnetic field in a gas mixture, the oxygen molecules move along rising field gradients and thus collect in the regions with high field intensities. In order to make this behavior of the oxygen visible, a dumbbell-shaped test piece is used, which is rotatably suspended in a gas in which there is a suitable inhomogeneous magnetic field. By means of the local compression of the paramagnetic oxygen molecules, a torque is exerted on the dumbbell-shaped test piece, which as a result rotates about the axis defined by the at least one tensioning wire, preferably through the centroid of the test piece. To measure said movement precisely, a mirror is used as part of a light balance, which measures the deviation of a light reflection from said mirror onto a photo sensor. In order to compensate for the movement of the test piece, a current is conducted through the conductor loop, which current interacts with the magnetic field and guides the test piece back into its resting position. The intensity of said current is then a measurement for the oxygen concentration.
It is known from DE 10 2006 021 308 B4 to vapor-deposit the conductor loop onto the surface of the test piece of a paramagnetic oxygen analyzer. In said prior art, the test piece is retained by an arrangement of springs that are situated in a planar manner in a plane together with the rotational plane of the test piece. Therefore, it is possible that the conductor loop is attached only on one side of the test piece, generally the upper side, and is galvanically connected to the springs, which conduct the current in order to generate the torque.
In an arrangement such as that in the preamble of said invention in which a test piece is rotatably retained by at least one tensioning wire, said configuration is, however, not possible since the tensioning wire is not situated in a planar manner in a plane together with the rotational plane of the test piece, but is largely perpendicular to said plane. There is therefore a need for an electrical line, which can also be part of the conductor loop, from the upper side to the lower side of the test piece, since the current is in this case conducted further to close the circuit. The technically certainly obvious vapor deposition of an electrical line over an edge and over a thin outer surface that would be required to guide a continuous conductor loop over a plurality of side surfaces of the test piece appears to be impractical, however.